I now find myself in need of a Class D o/p filter and can't help windering if I can make use of some of my stash! For a 100W/8Ohm application I seem to be looking for around 30uH that doesn't saturate at 5A.

Observations about the inductor: The shielding comes down all the way over the bobbin carrying the coil but leaves a narrow gap top & bottom where it's glued together with some kind of blue resin. The winding is bifilar and the pair are 20cm long wound in ten turns.http://www.tdk.co.jp/tvcl/equivalent/slf125xx.pdf also gives a parasitic R and C of 10k and 4pF.

So anyway, basic theory is fine with series/parallel connecting of inductors to arrive at different values - and shielding (if it works) should stop them interacting (!). I wonder if anyone can beat me to a conclusion before I slam 12 into two parallel strings of 6 to get 30uH @ 6.8A (DC 0.042 Ohm) and see how it goes?

Take some margin on current rating when using them in parallel. Inductance goes down with current below the actual full core saturation, so the one of lowest inductance in parallel connection takes the most current , which makes its inductance even lower.
This effect depends a bit on tolerance, but the ±20% you quote relates to the nominal value, not actual difference between any two of the same batch.
At DC the effect is however reversed, due to positive DCR coefficient due to heating.

Thanks! Many good points darkfenriz ~ yet while I'm still embarrassed about my drunken figures, the apparent reduction in parasitic capacitance still seems to be there. I'm about to build a test-bed with a PWM sig. gen and scope to characterise the results as this seems the best way to find out what I'll get anyway.